Pneumatic tire.



J'. MACDUNNELL.

PNEUMA'IIC TIRE.

APPLOATION FILED Mli. 25. 1909.

981,208. Patendmmwn.

yet if the backing is not capable of stretchi AMES MAoDONNELL, OF HAVERHILL, MASSACHUSETTS.

PNEUMATIC TIRE.

specification of'Letters raient.

Patented Jan. 1 0, 191 1.

Application filed March 25, 1909. Serial No. 435,573.

To all 'wiom it may] concern:

Be it known that l, Janes \l.\ 'l)o.\ .\ni.i., a citizen of the United States. residing at Haverhill. count-y of Essex, and State of Massachusetts, have invented an 'Improve nient in Pneumatic Tires, of'which the following description, in connection with the accompanying drawing, is a `specification, like letters on the drawing representing like parts.

It has heretofore been proposed to malte cned and made of rubber which is held under compression, so that if the tire is punctured the hole will be immediately sealed up as soon as the puncturing body is -withdrawn. This construction has been secured by molding the tire tread in a normally de.; pressed position and securing firmly to the exterior of the rubber body a stay strip of canvas or similar material, so that when the tire is intiated the non-stretching qualities of the stay strip will cause the rubber to be compressed. So far as I am aware in all prior attempts to make a tire of this type, the stay strip or backing has been inelastic both transversely and longitudinally. lVhile the inelastic quality in a direction transversely ofthe tire is essential to main-V tain the desired compression of the`rubber,

ing in a direction longitudinallyv of the tire, then when the tire is infiated. the circumferential length of the tread portion cannot be appreciably increased and the tire will assume its shape when infiated by a con pression longitudinally of that portion of the tire opposite the tread.

My present invention is in the nature of an improvement on tiresof this class and aims to provide a construction wherein when the tire is inflated the tread portion thereof is held against stretching in a transverse direction, thereby securing the desired compression of the rubber, while at the same time said tread portion can expand or stretch longitudinallyv to permit the tire to assume its inflated shape without subjecting the, portionof the tire opposite the tread to any appreciable longitudinal compression.

I accomplish my desired object by mak` ing the stay strip of such a character that it is incapableofstretching transversely but is on the other hand capable of stretching in a direction longitudinally of the tire.

' ln the drawings I have shown two embodiments of in v invention, 'but the invenin accordance with my invention, said ligure showing the forni which the tire assumes when it is not intiated; Fig. 2 is a similar view showing the tire after it is intinted; Fig. 3 .shows a 'plan view of a pory tion of the section of the tread portion of a pneumatic tire with a tread portion thiclz- 'especially designed for use as an inner tube in a double tube tire, but in the drawings I- have not deemed it necessary to show. the. shoe or outer casing, as the manner in which an inner tire is received Within the shoe Yis well known. -'l` he inner tube is shown at 3 and it is in the form of an endless tube of rubber which molded with the tread portion #l somewhat thicker than the other portions of the tire. The rubber tire has applied and firmly secured thereto a backing or stay strip 5 which has special character` istics as hereinafter described. The tire is molded in the form shown in Fig. l with the tread portion in a normally de ressed or concaved position, and during t e process of making the tire the stay strip 5 is firmly secured to the outer surface of the tread portion when in its` depressed position. ll'hile it is not essential to the invention that the envelop or stay strip 5 should entirely inclose the tire, yet I prefer to make it as herein shown, and to provide the edges 8 of the stay strip which extend about the portion of the tire adjacent the rim of the wheel Y with suitable means, vsuch as eyelets 9 by which they ma) be connected together by lacing 10.

The stay strip 5 is so made that it is incapable of stretching transversely of the tire, but is capable of stretching in .a direction longitudinally of the tire. Since the stay strip cannot stretch in a direction transversely of the tire it will be readily apparent that when the tire is inflated, as shown in Fig. 2, the rubber forming the thickened tread portion of the tire will be put under considerable compression due to the fact that the outer face of the rubber is not per i in a :irii-ij: ot' wav-p 'n g; Athe ,-iar -trip ito rut it on the lisas* that Q y Y '981,208

iuittid to expand because of the presence ot the .stay strip. lt will also be apparent that when the tread portion fr is fori-eil outwardly as' the tiro is inflated the eirftunference longitudinally of `said tread portion is 'aereased considerably in length, bnr owing to the l'aet that the -tay strip which l einpliy is i-;ip.1.hle oi -tretfchiiig longitudinally. the presence ot' the .stay .strip does' not interlere in any wa)v with such increase iii length.

'l'lie stay strip lnivin;r the ':ip-.aritv o .stretchinglongitudinally while being inrais. to so torni tin- .-tai' trip that the warp i incapable ol' stretchinir transversely lint which is capable of stretchingr longitudinally to perniit of the natural inflation of the tire.

Having fully described my invention, whatJ l claini new and desire to secure by Let,- ttls Patent lS- t. A pneumatic tire of rubber havingr its i the tread portion thereof can expand longiand wilt threads'exit-nd diagonali).v avro-s.

,-iav .-irip ie-ipalilioth stretching longitudiasit is, intlati-d. and sin'h longitudinal eil -tf-i' the stay strip ti'igether as will be l f 'Y onine. lhis tendency not only counteract-z any tendency ot' the s'trip to stretch transversely and thus iualtes the sta)- strip -Vinelai-tic transversely, but also tends to actually decrease theY width of the sta;1 strip and this angine-nts the compression iinilei which inirulilier foriniingr the tread portion l is placed.

te ln Figs. 5 and t I have shown :inothei' einiioilinient ot' in v invention wherein the stai' st rip is provniled with slits through its longitudinal stretching of the portion which overlie.- the tread ot`the tire. ln this ease the w i the s! i ,4t rip and the. weit threads extend traiisversel) thereof, but the `slits Q0 {.irined in the Stay stripperniit the necessary elon- .gi'it-ion thereof at the tread portion of the tire.

From the above it will be seen that my iiivintion eoinprehends the use of a stay strip foixseeiuing the desired compression of the 4Vtread 'portion of the tire which stay strip is tiidinall)v while the rubber forniiiig said tread portion is ,lield`iiiider compression L transversely.

2. pneumatic tire of rubber having the niaterial ot' its` tread portion iii a highlynall v as required lo accommodate the iii-i creasing;` circuitit'ireiitial length of the tiie compressed state iii a direction transversely ot the tire, and a stay strip tirinly secured to the outside of the tread portion, which stretching' results in tending to draw the' stay strip is non-stretehable in a direction transversely of the tire but is capable of stretching iu a direction longitudinally of the tire.

3w A pneumatic tire of rubber having the material of its tread portion in :i highlycompressed state in a direction transversely ot the tire. and a stay strip firmly secured to the outside thereof, which stay strip is foi-ined of a Woven fabric eut on the bias.

-t. .X pneumatic tire of riihber having the,

iiiaterial ot'l its tread portion in a highlyeonipressed state in a direction transversely central portion to peiinit of the nece-'sary eaiahle of stretchino in a direction lonffitut b r:

vrp threads: extend longitudinally of@ dinalfy of the tire and which is decreased in width h v such longitudinal stretching,

ln testimony whereof, I have signed my naine to this specification, in the presence of two subscribing Witnesses.

JAMES MACDONNELL. 

